I live in Alberta Canada and there is a Dino Museum, one of the biggest in the world in the 'badlands' where a huge portion of fossils have been found.

you walk through the building and its sectioned off into ages. They have a doorway with a signboard to read each time there was a mass extinction. Each one except for one was caused by cooling. the one that was not caused by cooling was caused by volcanos.

Strangely searching online gives me other 'answers' like a couple were due to global warming, but simply matching the ice age history https://geology.utah.gov/wp-content/uploads/ice_ages2.gif

with mass extinction history https://scx1.b-cdn.net/csz/news/800a/2019/graphiconear.jpg

and its clear that cold is the main cause mass extinction.

I ignored the crustaceous extinction as the current thought is it was due to an astroid and that obviously has nothing to do with earths ability to self regulate temperatures.

Yep